Exemplary embodiments relate to a nonvolatile memory device and a method of programming the same.
Recently, there is an increasing demand for nonvolatile memory devices which can be electrically programmed and erased and which do not require a refresh function of rewriting data at specific intervals.
The nonvolatile memory device can be electrically programmed and erased in such a manner that electrons within an oxide layer migrate in response to a strong electric field applied to the oxide layer, thereby shifting the threshold voltages of memory cells.
The nonvolatile memory devices may be typically used in mobile devices, and thus it is necessary to develop technology in which the same characteristic can be maintained despite a change of temperature. After a program operation for the memory cells of the nonvolatile memory device, a program verification operation is performed. A sense current used as a reference current in the program verification operation may be sensitive to a change of temperature. In particular, if the program operation and the program verification operation are performed at low temperature, a change of the sense current is increased to widen a threshold voltage distribution of the memory cells. Accordingly, there has been a need for technology capable of preventing the phenomenon in which the threshold voltage distribution of memory cells may be widened at low temperature.